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Abstract Detail


Evolutionary Developmental Biology (Evo-Devo)

Barth, Sina [1], Eimert, Klaus [1], Geier, Thomas [1], Gleissberg, Stefan [2].

KNOX overexpression in transgenic Kohleria (Gesneriaceae) plants affects later stages of leaf morphogenesis and leads to prolonged activity of the marginal blastozone with altered segment fate.

We present an analysis of leaf morphology and morphogenesis in transgenic Kohleria (Gesneriaceae) lines overexpressing the KNAP1 gene under the control of the CaMV-35 S promoter. KNAP1 is a KNAT1-like KNOX gene from apple (Malus domestica). Overexpression of KNOX genes have previously been shown to cause drastic leaf form changes, the nature of which depend on the wild-type morphology of the respective species. Kohleria, like many members of this family, has simple serrated leaves with pinnate venation. Transgene expression causes a relative reduction of the midvein and a more palmate venation with secondary veins forming prominent loops at segment sinuses. Basal, but not the apical part of leaf blades exhibited prolonged segment proliferation, that was greatly enhanced in leaves inserted below a decapitated shoot tip. Segment fate in these basal positions were altered from serrations to leaflet-like, basally narrowed blade parts on which higher-order segments developed for considerable time. Interestingly, marginal blastozones during early stages of leaf morphogenesis appeared similar in the wildtype and the transgenic lines. Only later stages of leaf morphogenesis led to the described effects in basal blade parts, where persistent marginal blastozones could be found. We conclude that different leaf parts and growth phases respond differently to KNOX gene upregulation.


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1 - Geisenheim Research Center, Institute of Biology, Von-Lade-Str. 1, Geisenheim, 65366, Germany
2 - Ohio University, Environmental and Plant Biology, Porter Hall, Athens, Ohio, 45701, USA

Keywords:
KNOX
Leaf dissection
marginal blastozone
Kohleria.

Presentation Type: Poster:Posters for Topics
Session: P
Location: Exhibit Hall (Northeast, Southwest & Southeast)/Hilton
Date: Sunday, July 8th, 2007
Time: 8:00 AM
Number: P70002
Abstract ID:1293


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